Current portable wireless communication terminals for military and field use have the ability to communicate with other similar devices over a large area and have map systems that show an abundance of information that can be shared. They also have the ability to send audio messages to the other terminals in form of peer to peer voice messages like the similar “walkie-talkie” technology.
However there are situations where large complex systems with maps and audio communication are not favorable, in certain field situations there are advantages to having a communication terminal that can be operated simply and that does not show unnecessary information; there are also certain situations where it is an advantage to communicate via text messages and not through audio messages, like in areas with a high noise level e.g. during an emergency, or a catastrophe, or areas where there is an advantage to keep a low noise level e.g. in a military operation. In these situations it is crucial that the unit is easy to operate and that the information shared by the different terminals does not reach the wrong person(s). In these situations it is also favorable to have the ability to communicate with all the other team units. In certain situations like in a rescue operation or in a military operation it is also an advantage to assign the different units one or more roles that can be displayed to the other units, reflecting the unit's tasks. This role must be possible to change, both from the unit itself, or from units with a relevant role. E.g. a team leader can assign roles to its team members, but if the team leader is taken out of operation another unit must be able to take the role as team leader.
It is known from FFI Fakta (http://www.mil.no/multimedia/archive/00086/Faktark-NORMANS-KKI-—86445a.pdf) that a system designated “Normans KKI” and “Normans ledelse” includes a unit (KKI) to be placed and integrated by wire on a soldier's dress in order to make information about positions of the soldier and designated team members show up on a display of the unit. The unit contains a digital magnetic compass and a GPS and also a simple message function enabling for example alarm messages. Passive sensors can be coupled to the unit. The “ledelse” unit is a handheld unit that shows the positions of all soldier units displayed on a digital map giving the leader an overview of his team. The “ledelse” unit is supplied with software for interactive planning with the units of the soldiers. Marching routes, way points or other battle related information can be put into the digital map. Also, active sensors can be coupled to the “ledelse” unit and information from passive sensors on the soldiers' units can be collected. The message functions of the “ledelse” units allow for sending and reception of maps, text, orders, alarms and positions.
The systems available at the present like the one in US 2006/0238331 A1 shows a communication unit mainly for military use that has a GPS based map interface displaying the location of other team units. This information is shared between the different team units by radio communication via a central unit that receives the information, organizes it and sends it back out to the different team units in the system in a strict hierarchy, using a master-slave configuration. The different team units can also receive audio messages either from the central unit or from each other. These team units have in addition to biosensors that monitors the pulse, temperature and blood pressure also abilities for iris scan of the user and a credit card chip for economic settlement.
Further it is known from U.S. Pat. No. 6,898,526 B2 a communication terminal system intended for hunters that has a GPS based map system and a radio communication device for communicating your position to a central unit, the central unit sends the location of the different team units to each team unit. The information is shown on a map interface with a compass bearing, the team unit then further communicates with the weapon in the form that it always knows where it is pointing and can stop the weapon from firing in the direction of other team units. This system does not have the ability to communicate any other information than the location information received from the GPS unit.
It is also known from U.S. Pat. No. 6,373,430 B1 a portable team unit with GPS and radio that communicates the location information from the GPS with one or more other equal team units. The location information is sent over the radio link to the other team units. This information is shown in a map interface so that everybody in the system can see where the others are by showing a unique identification tag for each team unit.
U.S. Pat. No. 6,456,938 B1 teaches a system for navigation at a golf course, having a screen for showing a map of the course. The system has messages, and can show distances and bearings. The units may communicate directly, but cannot relay messages, nor show other player's position.
US2005/0001720 A1 and US2008/096519 A1 both teach systems that tracks mobile terminals and where a unit can have a role as e.g. “leader”.
Neither of these documents have a solution to the problem of avoiding a third party from using a lost or compromised unit, or that a unit may be discovered, disturb other communications or use too much battery because it transmits with unnecessary high power.